Downmixed signal calculation method and apparatus

A downmixed signal calculation method, comprising:

• obtaining a downmix compensation factor of a previous frame when the previous frame of a current frame of a stereo signal is not a switching frame and a residual signal in the previous frame does not need to be encoded;
• obtaining a second downmixed signal in the current frame;
• correcting the second downmixed signal in the current frame based on the downmix compensation factor of the previous frame, to obtain a first downmixed signal in the current frame;
• and
• determining the first downmixed signal in the current frame as a downmixed signal in a preset frequency band of the current frame.

A downmixed signal calculation apparatus comprising:

• a memory for storing computer executable instructions;
• and
• at least one processor operatively coupled to the memory, the at least one processor being configured to execute the computer-executable instructions to:
• calculate a first downmixed signal in a current frame when a previous frame of the current frame of a stereo signal is not a switching frame and a residual signal in the previous frame does not need to be encoded, or when the current frame is not a switching frame and a residual signal in the current frame does not need to be encoded, wherein the at least one processor being configured to execute the computer-executable instructions to calculate a first downmixed signal in the current frame comprises the at least one processor being configured to execute the computer-executable instructions to:
• obtain a second downmixed signal in the current frame;
• obtain a downmix compensation factor of the current frame;
• and
• correct the second downmixed signal in the current frame based on the downmix compensation factor of the current frame, to obtain the first downmixed signal in the current frame;
• and
• determine the first downmixed signal in the current frame as a downmixed signal in a preset frequency band of the current frame, wherein

A downmixed signal calculation apparatus comprising:

• a memory for storing computer executable instructions;
• and
• at least one processor operatively coupled to the memory, the at least one processor being configured to execute the computer-executable instructions to:
• obtain a downmix compensation factor of a previous frame when the previous frame of a current frame of a stereo signal is not a switching frame and a residual signal in the previous frame does not need to be encoded;
• obtain a second downmixed signal in the current frame;
• correct the second downmixed signal in the current frame based on the downmix compensation factor of the previous frame, to obtain a first downmixed signal in the current frame;
• and
• determine the first downmixed signal in the current frame as a downmixed signal in a preset frequency band of the current frame.